Effects 11 is being provided as a porting aid for older code that makes use of the Effects 10 (FX10) API or Effects 9 (FX9) API in the deprecated D3DX9 library. See MSDN for a list of differences compared to the Effects 10 (FX10) library.

The Effects 11 library is for use in Win32 desktop applications. FX11 requires the D3DCompiler API be available at runtime to provide shader reflection functionality, and this API is not deployable for Windows Store apps on Windows 8.0, Windows RT,
or Windows phone 8.0.

The fx_5_0 profile support in the HLSL compiler is deprecated, and does not fully support DirectX 11.1 HLSL features such as minimum precision types. It is supported in the Windows 8.x SDK version of the HLSL compiler (FXC.EXE) and D3DCompile API (#46),
is supported but generates a deprecation warning with D3DCompile API (#47), and
could be removed in a future update.